1Snackbar.make(fragmentView, text, Snackbar.LENGTH_LONG).setAction("Action", null /* replace with your action or leave null to just display text*/).show();

1class MyApp extends StatelessWidget {
2  @override
3  Widget build(BuildContext context) {
4    return new MaterialApp(
5      title: 'Flutter',
6      theme: new ThemeData(
7        primarySwatch: Colors.blue,
8      ),
9      home: new MyHomePage(),
10    );
11  }
12}
13
14class MyHomePage extends StatefulWidget {
15  MyHomePage({Key key}) : super(key: key);
16
17  @override
18  _MyHomePageState createState() => new _MyHomePageState();
19}
20
21class _MyHomePageState extends State<MyHomePage> {
22
23  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
24
25  @override
26  void initState() {
27    super.initState();
28    showInSnackBar("Some text");
29  }
30
31  @override
32  Widget build(BuildContext context) {
33    return new Padding(
34            key: _scaffoldKey,
35            padding: const EdgeInsets.all(16.0),
36            child: new Text("Simple Text")
37    );
38  }
39
40  void showInSnackBar(String value) {
41    _scaffoldKey.currentState.showSnackBar(new SnackBar(
42        content: new Text(value)
43    ));
44  }
45}

1import * as React from 'react';
2import { View, StyleSheet } from 'react-native';
3import { Button, Snackbar } from 'react-native-paper';